Researching cures and treatments for cancer is an expensive proposition, and takes decades, to boot, so the country's top cancer research centers need the kind of deep and never-emptying pockets they only sew into billionaires' pants.

Now Johns Hopkins University is the latest major immunotherapy research center to get a life-altering donation from the super rich: Last month, the respected Baltimore institution received a $125 million pledge from a coalition of donors, anchored by twin $50 million checks from billionaires Michael Bloomberg and Sidney Kimmel.

That gift is an opportunity to reflect on where cancer research is going, and who's bringing new resources to the table.

Bloomberg, of course, is the business media tycoon and three-term mayor of NYC, and Sidney Kimmel is the founder of Jones Apparel Group and producer of several Hollywood films. We've written about Kimmel before, and he's a great example of why we created Inside Philanthropy. The guy is a mega-giver, with a huge footprint in cancer research, among other interests, but he doesn't tend to draw lots of attention. There are more and more Sidney Kimmels around these days.

The remaining $25 million in the Hopkins gift came from more than a dozen other supporters (hopefully, they won't feel slighted to be referred to as "other supporters" after giving a collective $25 million.)

Hopkins will use the enormous pledge to launch the new Bloomberg-Kimmel Institute for Cancer Immunotherapy. Johns Hopkins Medicine was, of course, already a well-funded and world-renowned research center. But a guaranteed $125 million is the kind of money that can pay for a lot of research that might otherwise not be conducted. Hopkins spokespeople are not afraid to say the research will lead to breakthroughs in control of the most serious cancers, and even cures.

Both Kimmel and Bloomberg have been major patrons of Johns Hopkins for a long time. Even before the new gift, there was already a Johns Hopkins Kimmel Cancer Center, named in recognition of the $157 million Kimmel has given since 2001, not to mention the $2.4 million to support early-career cancer scientists at Hopkins.

Bloomberg is a Hopkins alum, a 1964 graduate and chairman of the school's board of trustees from 1996 to 2002. This latest $50 million for immunology research adds to the pile of his previous giving to Hopkins—more than $1.2 billion, so far, to the university and the Johns Hopkins Health System. Bloomberg's money is in departments and schools all over the campus, and has financed 20 percent of need-based financial aid to undergrads, with another $350 million to recruit faculty members. No American has ever given more to a single university than Bloomberg. (Although, watch out—Gordon Moore is hot on Mike's trail with his huge giving to CalTech.)

But back to the bigger picture: It's safe to say Bloomberg and Kimmel's latest deal suggests that they believe there's real promise to immunotherapy. Along with them and Parker, Amazon's Jeff Bezos is another big backer of cancer immunotherapy research—he's delivered the field at least $30 million, possibly by drone.